How Does Wave Power Work?



Wave power or wave energy comes from the waves in the ocean. It is important to understand the difference between tidal power and wave power before we continue. Tides are created by the gravity of the moon and to a lesser extent the sun. This causes a bulging of the water on Earth that rotates with the moon thus creating higher and lower water levels at different times. Waves are created by the wind blowing across the surface of the water creating ripples. Of course, stronger winds means larger or stronger waves. There are a few different methods in use to generate electricity from wave energy. One popular version is the Pelamis Machine pictured to the right and below. It floats along the surface of the water anchored down on one end. The rolling motion of the waves generates electricity.

Pelamis Machine Wave Energy Converter

These wave energy generators were the first ever developed and put to use. Multiple pelamis machines combined created “wave farms” for generating offshore electricity. They are designed to be highly resistant to the forces of the open ocean and would be a very resiliant renewable energy source.

How does it work though? The rolling motion of the waves is resisted by hydraulics which pump oil through a hydrolic motor. This motor is what converts the wave motion to electricity by powering electrical generators.


Pelamis Machine

Wave Energy Buoys

While Pelamis Machines have been proven to work there are a few other technologies on the cusp of being put to use. One idea that has gotten a lot of attention is anchoring bouys to the ocean floor and generating electricity by the bobbing up and down. Not only does this generate electricity from moving up and down but also forward and backwards. Look at the image below to see the trajectory that an object floating on the ocean surface takes.


Trajectory of an object (energy buoy) on the surface of the ocean.

While energy buoys are a great idea and theoretically work will fine they haven’t been put to commercial use yet. However, in the near future we should begin to see wave energy farms using this technology as well.